Alcoa Rockdale’s Aluminum Atomizer fuels Space Program

By Annette Stone

Rockdale in the mid-20th century was a small rural town with an economy based on agriculture. It was a time of recovery from WW II. No one in the community envisioned a major industrial complex in the nearby countryside. The early 1950s brought change. Native son and author George Sessions Perry described that change in the Dec. 27, 1952 Saturday Evening Post article entitled “The Town Where It Rains Money.” Not just progress brought the new Aluminum Company of American smelter to town but the threat of another war in Korea as well. The purpose of the plant was to manufacture stores of aluminum for military use.

In 1966 Alcoa built an aluminum atomizing plant on the smelter site to provide powdered aluminum for use during the war in Vietnam. The atomizer had an ultimate capacity of 120 million pounds of powder per year. In the late 1970s the Rockdale atomizer became the major supplier for the United States Space Transportation System. Powdered aluminum was an important component of solid fuel used in shuttle boosters. The first STS lift-off into space was April 12, 1981.

Exposed to a spark an aluminum powder dust cloud can ignite and release a great deal of energy resulting in an explosion. The powder mixed with an oxidizer such as ammonium perchlorate and a binder called polybutadiene acrylonitrile (PBAN) becomes solid rocket fuel. The fuel has the consistency of an eraser. Its highly oxidative power creates the boost needed to propel a vehicle into space. The reaction inside the booster reaches 5,000 degrees Fahrenheit.

To make powdered aluminum large vessels transported molten aluminum from the smelter to the atomizing plant. Placed under high pressure and forced through a small aperture, the aluminum became miniscule droplets. Ductwork systems transported the powdered metal to storage containers.

Powder management at the atomizer was a complex job. Safeguards for transporting the atomized powder throughout the process included flame retardant clothing, specially made grounded boots and spark-resistant tools made of beryllium copper. After 1979, no major incidents occurred in the Rockdale atomizer due to increased safety requirements by government agencies and Alcoa corporate.

The atomizer produced a range of different-sized aluminum powders and granules for a variety of uses. Atomized aluminum is used as a feedstock for various chemical processes, paint pigments, commercial blasting agents and numerous aerospace and military applications.

A decline in the price of aluminum on the world market and the rising cost of energy shuttered the smelter in 2008. The atomizing plant continued manufacture of powdered aluminum until 2013.

Both the atomizer and smelter brought prosperity to Rockdale and the region. Jobs were plentiful, and young people could stay in the community rather than leaving to seek work. Alcoa gave generously to projects benefitting towns in the area.

The adage about history repeating itself seems to hold true for Rockdale. Closing of the two Alcoa plants created difficulties, but recent new growth in the area promises to bring economic stability to Rockdale in the coming years. It may not be raining money, but there is hope for the future.

Sources: Ray Kuchera, former Alcoa Operations Manager, Specialty Metals Division; John Garza, former Alcoa Operations Manager Specialty Metals Division; Terry Blodgett, Alcoa Rockdale Location Asset Manager; https://blogs.nasa.gov/Rocketology/tag/aluminum/; https://www.britannica.com/technology/space-shuttle